A/T - 3-4 Clutch Update
Bulletin: 93-74L60-3Date: March '93
Ref.No.: 93-118-74L60
Corp.Ref.No.: 377117
SUBJECT:
SMU - SECTION 7A-TRANSMISSION UNIT REPAIR UPDATE 3-4 CLUTCH
MODELS AFFECTED:
1991-93 ROADMASTER
New Product Information for 1993 HYDRA-MATIC 4L60 transmissions. This information has been updated since publication of the 1993 Service Manual and should be noted accordingly. Be certain to familiarize yourself with these updates to properly repair the 1993 HYDRA-MATIC 4L60.
DATE OF PRODUCTION CHANGE:
On January 05, 1993 (Julian Date 005) HYDRA-MATIC 4L60 transmissions were built with an improved design 3-4 clutch. The improved design consisted of combining the 3rd and 4th clutch ring retainer plate (Ill. 652), the 3rd and 4th clutch apply (stepped) plate (Ill. 653) and the 3rd and 4th clutch (steel) plate (Ill. 654C) into one 3rd and 4th clutch apply plate (Ill. 653) Figure 1. The 3rd and 4th clutch steel plates are also thicker and the backing plate selection has changed as noted in Figure 2.
NOTE:
In the overhaul repair kits for the HYDRA-MATIC 4L60 there are two (2) sets of 3rd and 4th clutch fiber plates. The two 3rd and 4th clutch fiber plates are calibration sensitive and interchanging the wrong plates may cause premature failure. The chart shows which models should use the plates labeled "2050" Figure 3.
Figures 1 Thru 3
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